NAME

env – environment variables

SYNOPSIS

bind #e /env

/env/var1/env/var2
...

DESCRIPTION

The
env
device serves a one-level directory containing files with arbitrary names
and contents.
The intention is that the file name is the name of an
environment variable
(see
rc(1)),
and the content is the variable’s current value.

When a
fork(2)
system call creates a new process, both the parent and the
child continue to see exactly the same files in the
env
device: changes made in either process can be noticed by the other.
In contrast, an
rfork
system call with the
RFENVG
bit set (see
fork(2))
causes a split: initially both process groups see the
same environment files, but any changes made in one process group
cannot be noticed by the other.
An
rfork
with
RFCENVG
splits and then clears the environment.

The special global environment
#ec
contains kernel configuration variables,
such as those set in
plan9.ini(8).
All processes see the same
#ec;
its contents are writable only by the host owner.